/*
 * Copyright 2002-2013 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package org.springframework.security.web.util.matcher;

import javax.servlet.http.HttpServletRequest;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.security.web.util.matcher.RequestMatcher;
import org.springframework.util.Assert;

/**
 * A {@link RequestMatcher} that will negate the {@link RequestMatcher} passed
 * in. For example, if the {@link RequestMatcher} passed in returns true,
 * {@link NegatedRequestMatcher} will return false. If the {@link RequestMatcher}
 * passed in returns false, {@link NegatedRequestMatcher} will return true.
 *
 * @author Rob Winch
 * @since 3.2
 */
public class NegatedRequestMatcher implements RequestMatcher {
    private final Log logger = LogFactory.getLog(getClass());

    private final RequestMatcher requestMatcher;

    /**
     * Creates a new instance
     * @param requestMatcher the {@link RequestMatcher} that will be negated.
     */
    public NegatedRequestMatcher(RequestMatcher requestMatcher) {
        Assert.notNull(requestMatcher, "requestMatcher cannot be null");
        this.requestMatcher = requestMatcher;
    }

    public boolean matches(HttpServletRequest request) {
        boolean result = !requestMatcher.matches(request);
        if(logger.isDebugEnabled()) {
            logger.debug("matches = " + result);
        }
        return result;
    }

    @Override
    public String toString() {
        return "NegatedRequestMatcher [requestMatcher=" + requestMatcher + "]";
    }
}